This application claims priority to International Application No. PCT/GB99/04077 which was published on Jun. 29, 2000.
1. Field of the Invention
The invention relates to a vacuum cleaner particularly, but not exclusively, to an autonomous or robotic vacuum cleaner.
2. Background of the Invention
Various proposals have been made in respect of autonomous or robotic vacuum cleaners, which are driven automatically and do not require to be propelled by a user across a surface to be cleaned. Essentially, such a vacuum cleaner comprises a body or chassis supported on wheels which are driven by a self-contained power pack and guided by a control system which navigates the vacuum cleaner around a room so that the floor or floor covering can be cleaned. For this purpose, the cleaner will also incorporate a cleaner head having a suction opening communicating with a dirt or dust collection device so that dirt and dust can be sucked up from the surface to be cleaned, separated from the airflow and stored in a container for disposal. Devices of this nature are shown and described in WO 97/40734 and WO 97/41451.
One of the disadvantages associated with devices of this type is that, in order for the machine to be able to manoeuvre into and out of small spaces, the device preferably has an essentially circular shape when seen in plan view. This allows the device to rotate about its own vertical axis when it has entered a restricted area so that it can turn around and locate a way out. Since any protrusion beyond the circular shape of the body will restrict the manoeuvreability of the device, the suction opening of the cleaner head is inevitably spaced away from the lateral extremity of the cleaner. This means that, when the cleaner is vacuuming along a wall or other edge of the area to be cleaned, the brush housed within the cleaner head cannot get as close to the wall or edge as existing vacuum cleaners which are manoeuvred by a user.
It is an object of the present invention to provide a vacuum cleaner of the type described above which can operate in close proximity to a wall or other edge. It is another object of the present invention to provide a vacuum cleaner of the type described above which can operate in close proximity to a wall or other edge without restricting the manoeuvrability of the vacuum cleaner. It is a further object of the present invention to provide a vacuum cleaner of the type described above which is capable of manoeuvring past small obstacles without becoming lodged. It is a further object of the present invention to provide a vacuum cleaner of the type described above which is capable of cleaning a larger proportion of the surface to be cleaned than known vacuum cleaners of this type.
The invention provides a vacuum cleaner comprising a body having supporting wheels, drive means for driving the wheels so as to propel the vacuum cleaner in a direction across a surface to be cleaned, dust and dirt separating apparatus and a fan for drawing air into the dust and dirt separating apparatus, the vacuum cleaner also having a cleaner head mounted beneath the body, transversely to said direction, and incorporating a dirty air inlet facing the surface to be cleaned, characterised in that the cleaner head protrudes transversely beyond the body on at least one side of the vacuum cleaner.
Providing a cleaner head which protrudes transversely beyond the body on at least one side of the vacuum cleaner means that, at least on the side on which the cleaner head protrudes, the vacuum cleaner is able to clean closer to a wall or other obstacle than previously known vacuum cleaners of the type described above. This arrangement provides a higher standard of cleaning than known vacuum cleaners and increases the product satisfaction of consumers.
In a preferred embodiment, the cleaner head is movable transversely with respect to the body so as to reduce or eliminate the protrusion thereof beyond the body. This arrangement allows the cleaner head to be retracted beneath the body of the vacuum cleaner so that, if the vacuum cleaner is required to manoeuvre within a confined area, the protruding cleaner head does not restrict the manoeuvreability of the vacuum cleaner. The transverse moveability of the cleaner head also allows the cleaner head to retract when small obstacles are located within the path of the cleaner head and this avoids the need to divert the whole vacuum cleaner from its previous direction of travel.
This arrangement is particularly advantageous for cleaners which have a body that is substantially circular in plan view. However, it can also be used on cleaners having bodies which are not circular.